code: def cuda(self):
      self.actor.cuda()
      self.actor_target.cuda()
      self.critic.cuda()
      self.critic_target.cuda()
  
imports: import numpy
  import torch
  import torch.nn
  from torch.optim import Adam
  from .memory import SequentialMemory
  from .utils import to_numpy, to_tensor
label_desc: Use image node_id 4 for calling the DDPG obj's underlying member method code with example usage: obj.cuda() without return types